Thomas Kevin Hopkins

US Patent:

6547353, Apr 15, 2003

Filed:

Jul 27, 1999

Appl. No.:

09/361705

Inventors:

Thomas L. Hopkins - Mundelein IL

Assignee:

STMicroelectronics, Inc. - Carrollton TX

International Classification:

B41J 2938

US Classification:

347 12, 323281, 323316

Abstract:

A thermal ink jet printhead system has a printhead with base member and a plurality of ink flow channels formed in the base member that connect to an ink reservoir and terminate in a nozzle through which ink is expelled. A heating element is associated with each ink flow channel. A monolithically integrated multiple output power driver circuit is formed as a semiconductor integrated circuit and connected to each heating element in the printhead. The multiple output driver circuit includes a power MOS transistor connected to each heating element. A reference circuit is operatively connected to each gate of the power MOS transistor and includes a reference transistor having a gate and a reference amplifier that receives as inputs a reference voltage and a source of current. An amplifier output is operatively connected to the gates of the power output transistors and the gate of the reference transistor. The reference amplifier regulates the reference transistor directly and the power MOS transistors by matching.

US Patent:

6633145, Oct 14, 2003

Filed:

Nov 20, 2001

Appl. No.:

09/991325

Inventors:

Jianwen Shao - Schaumburg IL
Dennis C. Nolan - Elk Grove Village IL
Kwan A. Haughton - Bartlett IL
Thomas L. Hopkins - Mundelein IL

Assignee:

STMicroelectronics, Inc. - Carrollton TX

International Classification:

H02P 118

US Classification:

318254, 318459, 318500, 318599, 318138, 318439, 3889281, 388804, 388806, 388811, 388822

Abstract:

A system and method of advancing the commutation sequence of a brushless DC motor is provided. The motor having a plurality of coils, each of the coils coupled together at one end to a common center tap and coupled at an opposite end, through a respective coil tap, to both a source voltage and ground via selectively actuateable switches having diodes coupled in parallel therewith. The motor operates in a pulse width modulation (PWM) mode having PWM-on states and PWM-off states. During PWM-off states, a coil tap voltage from the coil tap of a floating phase is provided to a preconditioning circuit. The preconditioning circuit adjusts the floating phase coil tap voltage to compensate for an amount of voltage substantially equal to an amount of voltage by which a voltage at the center tap deviates from zero. The preconditioning circuit further includes sharpening circuitry for amplifying the adjusted floating phase coil tap voltage. A signal output from the preconditioning circuit is provided to a zero-crossing detection circuit for detecting zero-crossing and determining when to advance in the commutation sequence.

US Patent:

7242175, Jul 10, 2007

Filed:

Aug 8, 2003

Appl. No.:

10/637985

Inventors:

Jianwen Shao - Rolling Meadows IL, US
Thomas L. Hopkins - Mundelein IL, US

Assignee:

STMicroelectronics, Inc. - Carrollton TX

International Classification:

G01R 25/00

US Classification:

324 7677, 32420725, 318439

Abstract:

A device and method that determine a freewheeling rotation of an electric motor. The method includes steps of measuring first and second signals from respective first and second windings of an unenergized motor, and determining from the first and second signals whether the unenergized motor is rotating. The method may also include determining from the first and second signals the direction of rotation if the unenergized motor is rotating. The method may further include measuring a third signal from a third winding of the unenergized motor, and determining whether the motor is rotating may include determining that the motor is not rotating if the first, second, and third signals are equal. The first and second signals may each include a respective back voltage.

US Patent:

7323823, Jan 29, 2008

Filed:

Feb 17, 2005

Appl. No.:

11/059955

Inventors:

Thomas L. Hopkins - Mundelein IL, US

Assignee:

STMicroelectronics, Inc. - Carrollton TX

International Classification:

H05B 37/00

US Classification:

315219, 315224, 315307

Abstract:

A fluorescent lamp assembly includes a fluorescent lamp ballast capable of detecting at least one of a plurality of input signals and generating an output signal. The output signal is associated with a power level that is based on the at least one detected input signal. The fluorescent lamp assembly also includes a fluorescent lamp capable of receiving the output signal and generating light. An intensity of the light is based on the power level associated with the output signal.

US Patent:

7541745, Jun 2, 2009

Filed:

Nov 21, 2007

Appl. No.:

11/986460

Inventors:

Thomas L. Hopkins - Mundelein IL, US

Assignee:

STMicroelectronics, Inc. - Carrollton TX

International Classification:

H05B 37/02

US Classification:

315219, 315224, 315307

Abstract:

A fluorescent lamp assembly includes a fluorescent lamp ballast capable of detecting at least one of a plurality of input signals and generating an output signal. The output signal is associated with a power level that is based on the at least one detected input signal. The fluorescent lamp assembly also includes a fluorescent lamp capable of receiving the output signal and generating light. An intensity of the light is based on the power level associated with the output signal.

US Patent:

8041052, Oct 18, 2011

Filed:

Mar 8, 2007

Appl. No.:

11/683645

Inventors:

Thomas L. Hopkins - Mundelein IL, US

Assignee:

STMicroelectronics, Inc. - Coppell TX

International Classification:

H04B 3/00

US Classification:

381 81, 381 80, 381 85, 381123

Abstract:

An audio selection circuit. The audio selection circuit includes a control/switch circuit having a first input, a second input, and a first output, and a signal detector module configured to detect an audio signal on the second input. If the signal detector detects presence of the audio signal on the second input, the signal detector is configured to transmit a control signal to the control/switch circuit, and the control/switch circuit is configured in response to the control signal to disconnect the first input from the first output and to connect the second input to the first output. Otherwise, the control/switch circuit is configured to connect the first input to the first output and to disconnect the second input from the first output.

US Patent:

8140870, Mar 20, 2012

Filed:

Jul 22, 2009

Appl. No.:

12/507661

Inventors:

Thomas L. Hopkins - Mundelein IL, US

Assignee:

STMicroelectronics, Inc. - Carrollton TX

International Classification:

H03K 3/017

US Classification:

713300, 713310, 713320, 713321, 713322, 713323, 713324, 713330, 713340, 327172, 327173, 327174, 327175, 327176

Abstract:

A forward converter circuit includes a transformer having a primary winding and a secondary winding. A first transistor is coupled in series with the primary winding and a second transistor is coupled in series with the secondary winding. A control circuit generating control signals for controlling operation of the first and second transistors. The control signals are generated responsive to the values in certain triggered counting circuits satisfying programmable thresholds.

US Patent:

8310293, Nov 13, 2012

Filed:

Jun 8, 2010

Appl. No.:

12/796278

Inventors:

Thomas L. Hopkins - Mundelein IL, US

Assignee:

STMicroelectronics, Inc. - Coppell TX

International Classification:

H03K 3/017

US Classification:

327176, 327142, 327177

Abstract:

A forward converter circuit includes a transformer having a primary winding and a secondary winding. A first transistor is coupled in series with the primary winding and a second transistor is coupled in series with the secondary winding. A control circuit generates PWM control signals for controlling operation of the first and second transistors. The control signals are generated responsive to source PWM signals processed through programmable delay timers to generate set/reset control signals which set an output PWM control signal duty cycle.